MOLLUSC A. 6 1 



smells like India ink or Sepia, and may be used as a 

 pigment, though this color is often made artificially. 



Cuttle-fishes are flatter and broader bodied than 

 Squids, and have, in place of a horny pen, a curious 

 structure. Buy a cuttle-fish bone, and you can see 

 readily that the outside is not bone, but a hard shell, 

 and the inside filled with a curious chalky deposit in 

 layers, but in no respect resembling a bone. The 

 Squids and Cuttle-fishes have ten arms around the 

 mouth and side fins. The eight-armed Devil-fish, 

 Poulp, or Octopus, is found on our coast, also, but 

 only of small size, and in deep water. 



The Argonauta, about whose beautiful shell so many 

 popular traditions have been woven, crowns this group 

 in a becoming manner. 



And as many of the popular books are in error about 

 the last named, it may be as well to mention, that the 

 Argonauta never sails on the surface with its outspread 

 arms, but prosaically swims, squirting its way back- 

 wards like the Squid. 



But while we have lost the tradition, we have gained 

 something of more value, — the knowledge that this is 

 not a true shell fastened to the body by muscles, but an 

 excretion, partly of the mantle, and of the edge of the 

 mantle, and of the great sail-like arms, which are thrown 

 backwards over and closely envelope the shining white 

 surface ; and that it is simply a lovely case built by the 

 female to protect herself and the large bunches of eggs 

 which she carries. 



Fig. 43 shows the female, with six arms extended, 

 in the act of swimming backwards ; one of the other 

 two arms, with its broad membrane, is shown as a 



